RebalanceController.getPlan(Cluster finalCluster,
int batchSize)
Construct a plan for the specified final cluster & batchSize given the
current cluster/stores & configuration of the RebalanceController.

RebalanceController.getPlan(Cluster finalCluster,
java.util.List<StoreDefinition> finalStoreDefs,
int batchSize)
Construct a plan for the specified final cluster/stores & batchSize given
the current cluster/stores & configuration of the RebalanceController.